Tamper evident closures are typically fitted over container openings by the manufacturer, and provide visual indication to the consumer if the closure has been opened or otherwise tampered with. Typically, tamper evident closures have a feature that must be dislocated or ruptured in order to open the closure (e.g., a seal that must be broken), and once dislocated or ruptured cannot be returned to its initial state, thus clearly indicating the closure has been opened. Examples of such lids include U.S. Pat. No. 5,875,908 and U.S. Pat. No. 6,341,707.
Such closures often have teeth that engage with the container and prevents opening of the closure unless the tamper evident feature is dislocated or ruptured. The teeth should be able to sufficiently engage with the container and should be sufficiently robust to prevent opening of the closure without dislocating or rupturing the tamper evident feature. However, limitations in the manufacturing process and/or the process of fitting the closure over the container opening may result in the teeth being insufficiently engaged with the container and/or insufficiently robust.
In the case of snap-on closures, it may also be desirable to ensure that the closure can provide a liquid-tight seal similar to that provided by screw-on closures.